Technical Field
The present disclosure relates to a nonvolatile memory devices and, more particularly, to operating methods of nonvolatile memory devices.
Discussion of Related Art
In general, semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices. Volatile memory devices lose their stored data when their power supplies are interrupted. Volatile memory devices include a dynamic RAM (DRAM) and a static RAM (SRAM). Nonvolatile memory devices retain their stored data even when their power supplies are interrupted. Nonvolatile memory devices include a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), a phase change RAM (PRAM), a resistive RAM (RRAM), and a flash memory.
In recent years, nonvolatile memory devices have been developed as three-dimensional structures with improved integration density. Three-dimensional nonvolatile memory devices exhibit improved write speed, improved cell lifetime, and improved power efficiency. A three-dimensional nonvolatile memory device and a conventional two-dimensional nonvolatile memory device are structurally different from each other. Due to the structural differences between the three-dimensional and two-dimensional nonvolatile memory devices, various methods for driving three-dimensional nonvolatile memory devices have been studied.